Why did the Hmong help the United States in the Vietnam War?

The Hmong, who lived mostly in the mountainous regions of Laos, were fiercely protective of their autonomy, especially their culture, which they perceived as being threatened by the spread of communism. They were not, per se, pro-United States, but were fighting to maintain their their independence. But they proved willing allies of the United States, which recruited thousands of Hmong to serve in combat, partisan activities, and espionage against Laotian Communists and the North Vietnamese Army. The Central Intelligence Agency (CIA) was especially instrumental in recruiting Hmong. They died in massive numbers, from combat, Communist reprisals, and from destruction of their farms. After the conflict, many Hmong fled the region, moving to Thailand or the United States.